Three dimensional displays are receiving increasing interest and significant research is undertaken in how to provide three dimensional viewing perceptions without requiring the user to wear specific glasses or other inconvenient equipment, or requiring the users eyes to remain in a specific location.
Three dimensional (3D) displays add a third dimension to the viewing experience by providing a viewer's two eyes with different views of the scene that is being watched. This can be achieved by having the user wear glasses to separate two views that are displayed. However, as this may be considered inconvenient to the user, it is in many scenarios preferred to use auto-stereoscopic displays that use means at the display (such as lenticular lenses, or barriers) to separate views, and send them in different directions where they individually may reach the user's eyes.
The auto-stereoscopic displays typically produce “cones” of views where each cone contains two or often more views that correspond to different viewing angles of a scene. The viewing angle difference between adjacent views is generated to correspond to the viewing angle difference between a user's right and left eye. Accordingly, a viewer whose eyes see two adjacent views will perceive a three dimensional effect. An example of such a system wherein nine different views are generated in a viewing cone is illustrated in FIG. 1.
However, although the described auto-stereoscopic displays provide a very advantageous three dimensional experience, they also have some associated disadvantages. For example, auto-stereoscopic displays tend to be highly sensitive to the viewers position and therefore tend to be less suitable for dynamic scenarios wherein it cannot be guaranteed that a person is in a very specific location. Specifically, correct three dimensional perception is highly dependent on the user being located such that the user's eyes perceive views that correspond to correct viewing angles. However, in some situations, the user's eyes may not be located optimally for receiving suitable image views, and therefore some auto-stereoscopic displays applications and scenarios, in particularly those where in appropriate views are directed to the eyes of the viewer, may have a tendency to confuse the human visual system leading to an uncomfortable feeling. Such an experience may not be restricted to users in locations wherein incorrect views are received but may even be experienced when a human does not directly look at the display but only sees it as part of his peripheral vision. The experience may be particularly pronounced for embodiments wherein people may move along the display thereby passing through a number of views.
Hence, an improved three dimensional design system would be advantageous and in particular a system allowing increased flexibility, an improved user experience, reduced user discomfort and/or improved performance would be advantageous.